Use Of Compounds Revealing The Efficiency Of Filterability Additives In Hydrocarbon Distillates, And Synergic Composition Containing Same

ABSTRACT

The invention relates to the use, in a hydrocarbon distillate with a boiling temperature of between 150 and 450° C. and a crystallization onset temperature as measured by Differential calorimetric Analysis of greater than or equal to −50° C., preferably of −5° C. to +10° C., of a homopolymer obtained from an olefinic ester of carboxylic acid of 3 to 12 carbon atoms and from a fatty alcohol containing a chain of more than 16 carbon atoms and optionally an olefinic double bond, as a compound for revealing the efficiency of filterability additives based on copolymer and/or terpolymers of ethylene and of vinyl ester of a carboxylic acid of 3 to 12 carbon atoms, and of a monoalcohol containing 1 to 10 carbon atoms. The invention is also directed to an additive composition comprising a conventional hydrocarbon filterability additive in combination with an efficiency reveal additive, and also to the combustion fuels, motor fuel and oil fuel that comprise these additive combinations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 12/373,261, filed on Jan. 9, 2009, which claims priority toInternational Patent Application No. PCT/FR2007/001153, filed Jul. 6,2007, claiming priority to French Patent Application No. FR 06/06254,filed Jul. 10, 2006, all of which are incorporated by reference herein.

BACKGROUND AND SUMMARY

The invention relates to the use in hydrocarbon distillates, for whichthe onset crystallization temperature of paraffins is greater or equalto −5° C., of an agent revealing the efficiency of conventionaladditives for filterability of hydrocarbons, as regards the limitingfilterability temperature of these distillates and of their flowtemperature at low temperatures. The invention is also directed to anadditive composition comprising a standard additive for filterability ofhydrocarbons in combination with an efficiency revealing agent as wellas to combustion fuels, fuel and fuel oil comprising these combinationsof additives.

The petroleum industry has been developing for a long time additivespromoting filterability of fuels at low temperatures. These additives,called LFT (Limiting Filterability Temperature) additives, have the roleof limiting the size of the crystals of the formed paraffins so thatthey may pass through the filters positioned inside internal combustionengines or in heating installations. This type of additives, very widelyknown to one skilled in the art, is systematically added to the middledistillates of conventional type used as diesel fuels or heating oil.

The prior art describes the use of other products having a synergiceffect with the known filterability additives, notably polymers ofethylene and vinyl acetate and/or vinyl propionate, as regards theimprovement in the limiting filterability temperature and flowtemperature at low temperatures of hydrocarbon distillates of aconventional type. Thus, U.S. Pat. No. 3,275,427 describes a middledistillate from a cut of distillation comprised between 177 and 400° C.containing an additive consisting of 90 to 10% by weight of an ethylenecopolymer comprising 10 to 30% of vinyl acetate units with a molecularweight comprised between 1,000 and 3,000 and of 10 to 90% by weight of apolylauryl acrylate and/or polylauryl methacrylate with a molecularweight ranging from 760 to 100,000. It is noted that these polyacrylatesimprove the filterability temperature determined according to the NFEN116 standard without deteriorating the flow point temperature asdetermined by the NF 60105 standard while the ethylene and vinyl acetatecopolymer improves flow.

For the transport of crude oils and heavy distillates via pipeline, theauthors of U.S. Pat. No. 3,726,653 were confronted with the improvementof flow notably at low temperatures at which these products mightcongeal in the pipelines. In order to improve these properties inhydrocarbon compositions containing paraffins, 5-20% by weight of whichhave a boiling point above 350° C. and a softening point above 35° C.,the inventors proposed adding to these compositions 10 ppm to 2% byweight of a polymeric mixture of an olefinic ester of carboxylic acidswith 3 to 5 carbon atoms with an alcohol with 14 to 30 carbon atoms andwith a molecular weight ranging from 1,000 to 1,000,000, with a ethyleneand vinyl acetate copolymer comprising from 1 to 40, preferably from 14to 24 units of vinyl acetate with an average molecular weight of 20,000to 60,000, the polymeric molar ratio of olefinic ester over ethylene andvinyl acetate copolymer ranging from 0.1 to 10:1.

In order to control the size of the crystals of paraffins present atcontents less than 3% in middle distillates having a boiling pointcomprised between 120° and 480° C., the authors of U.S. Pat. No.4,153,422 propose adding to these middle distillates 10 ppm to 1% byweight of a mixture of a homopolymer of an olefinic ester of acrylic ormethacrylic acid comprising an alkyl chain with 14 to 16 carbon atomsand a molecular weight ranging from 1,000 to 200,000, with an ethyleneand vinyl acetate copolymer with a number average molecular weight lessthan 4,000, the homopolymeric molar ratio of olefinic ester overethylene and vinyl acetate copolymer ranging from 0.1:1 to 20:1. But,with the increasing variety of sources of middle distillates, thepresent middle distillates stemming from the mixture of these sources,such as diesel fuels and fuel oils, now have very different compositionsfrom those of the middle distillates produced previously and for whichthe filterability additives notably those based on ethylene and vinylacetate and/or ethylene and vinyl propionate copolymers, have beendeveloped. Further, the change in specifications since the year 2000,and more recently in 2005, has led the refiner to distinctly formulatethe distillates for use as diesel fuels in engines, and domestic fueloils used in heating installations.

The distillates used are generally derived from more complex refiningoperations than those stemming from direct distillation of hydrocarbons,and may originate from cracking, hydrocracking and catalytic crackingmethods and from viscosity breaking methods. With the increasing demandin diesel fuels, the refiner tends to want to introduce cuts which aremore difficult to utilize, in these fuels, such as the heaviest cutsfrom these cracking and viscosity breaking methods which are loaded withheavy paraffins, i.e. comprising more than 18 carbon atoms. Further,synthetic distillates originating from transformation of gas such asthose from the Fischer Tropsch method, but also those resulting from thetreatment of biomass of vegetable or animal origin, such as notablyNexBTL and the distillates comprising esters of vegetable or animal oilshave appeared on the market and form a new range of products which maybe used as a fuel base and/or domestic fuel oil base also comprisingparaffinic chains with about 18 carbon atoms or more.

It was seen that the filterability temperature of the distillatesobtained by combining the old bases and these new sources is improvedwith difficulty by adding a conventional filterability additive becauseof the significant presence of normal paraffins with more than 18 carbonatoms and in particular of the complex distribution of normal paraffinsin their composition. Indeed, in these novel combinations ofdistillates, discontinuous paraffin distributions making the knownfilterability additives unsuitable were noticeable. Further, the arrivalof novel crude oils was seen on the market, which are much richer inparaffins than those commonly refined and for which the filterabilitytemperature of distillates from direct distillation was improved withdifficulty by the conventional filterability additives in the same wayas those mentioned earlier.

In the documents of the prior art, the authors therefore usecombinations of alkylene vinyl ester polymers with vinyl polyesters inorder to solve the majority of the problems for improving the flow pointand the filterability temperature for distillates of a conventionaltype, and they do not give any indication for solving the specificproblems associated with novel hydrocarbon distillates, for which theonset crystallization temperature of the paraffins is close to zeroand/or the normal paraffin content containing more than 18 carbon atomsis larger than 4%. Therefore there is a need for adapting thefilterability additives to these novel types of distillates.

Thus, this invention is not only applied to distillates stemming fromdirect distillation of hydrocarbons derived from crude oils which arevery loaded with paraffins but also and especially to hydrocarbonsderived from the heaviest cuts of refining operations, i.e. fromcracking, hydrocracking, and catalytic cracking methods and viscositybreaking methods or further synthetic distillates stemming fromtransformation of gas such as those stemming from the Fischer Tropschmethod, but also those resulting from the treatment of vegetable oranimal biomass, such as notably NexBTL and the distillates containingesters of vegetable and/or animal oils, either taken alone or as amixture. One of the routes selected by the applicant is that ofimproving the activity of conventional filterability additives asregards the limiting filterability temperature of middle distillates byadding another polymer as an agent for revealing the efficiency of theconventional filterability additives present in the middle distillate byproducing a synergic effect.

For this purpose, the present invention proposes the use in ahydrocarbon distillate with a boiling temperature comprised between 150and 450° C. and with an onset crystallization temperature, as measuredby Differential Scanning calorimetry Analysis greater than or equal to−5° C., preferably from −5° to +10° C., of a homopolymer obtained froman olefinic ester of a carboxylic acid with 3 to 12 carbon atoms and ofa fatty alcohol comprising a chain with more than 16 carbon atoms andoptionally an olefinic double bond, as a compound for revealing theefficiency of filterability additives based on a copolymer and/orterpolymer of ethylene and vinyl ester of a carboxylic acid with 3 to 5carbon atoms and of a mono-alcohol comprising 1 to 10 carbon atoms.Preferably, the hydrocarbon distillate comprises a weight content ofn-paraffins containing more than 18 carbon atoms, larger than 4%.Preferably, the hydrocarbon distillate comprises a weight content ofn-paraffins larger than or equal to 0.7%, the carbon number of which islarger than 24, preferably a mixture from 0.7 to 2% by weight ofn-paraffins having a carbon number ranging from C₂₄ to C₄₀.

According to one embodiment, the filterability additives are ethylenecopolymers containing more than 20% of ester units. Preferably, thefilterability additives are selected from copolymers of ethylene andvinyl acetate, of ethylene and vinyl propionate, of ethylene and ofvinyl versatate, of ethylene and (alkyl)acrylates, of ethylene and(alkyl)methacrylates, either taken alone or as a mixture, comprisingfrom 20 to 40% by weight of ester units. According to a preferredembodiment, said esters are of the vinyl acetate, vinyl priopionate,vinyl versatate, (alkyl)acrylate and (alkyl)methacrylate type, the alkylgroup containing from 1 to 7 carbon atoms.

According to one embodiment, the homopolymer is obtained bypolymerization of an olefinic ester of acrylic acid optionallysubstituted with an alkyl group having from 1 to 7 carbon atoms, and ofan alcohol comprising more than 16 carbon atoms, preferably from 18 to50 carbon atoms, the homopolymer having a weight average molecularweight Mw comprised between 5,000 and 20,000, preferably comprisedbetween 10,000 and 19,000. According to a particular embodiment, thehomopolymer is a polyacrylate comprising side hydrocarbon chains withfrom 18 to 40 carbon atoms. According to a particular embodiment, thedistillate is selected from distillates with a boiling temperaturecomprised between 150 and 450° C., comprising distillates from directdistillation, in vacuo distillates, hydrotreated distillates,distillates stemming from catalytic cracking and/or hydrocracking ofdistillates in vacuo, the distillates resulting from conversion methodsof the ARDS (atmospheric residue desulfurization) type and/or viscositybreaking methods, from valuation of Fischer Tropsch cuts, anddistillates resulting from BTL conversion of vegetable and/or animalbiomass, and distillates containing alkyl esters of vegetable or animaloils either taken alone or as a mixture.

According to another object, the invention relates to a compositioncomprising a mixture consisting of

-   A) a filterability additive based on a copolymer and/or terpolymer    of ethylene and of a vinyl ester of a carboxylic acid with 3 to 5    carbon atoms and of a mono-alcohol comprising 1 to 10 carbon atoms    and-   B) a homopolymer of an olefinic ester of a carboxylic acid with 3 to    12 carbon atoms and of a fatty alcohol comprising more than 16    carbon atoms, A and B being in a ratio producing a synergic effect    as regards the filterability temperature LFT as measured according    to the NF EN116 standard, of hydrocarbon distillates with a boiling    temperature comprised between 150 and 450° C. and with an onset    crystallization temperature as measured by differential scanning    calorimetry analysis, greater than or equal to −5° C., preferably    from −5 to +10° C.

According to another object, the invention relates to a compositioncomprising (A) from 85 to 99% by weight of at least one filterabilityadditive based on a copolymer and/or terpolymer of ethylene and of avinyl ester of a carboxylic acid with 3 to 5 carbon atoms and of amono-alcohol comprising from 1 to 10 carbon atoms, and (B) from 1 to 15%by weight of a homopolymer of an olefinic ester of a carboxylic acidwith 3 to 12 carbon atoms and of a fatty alcohol comprising more than 16carbon atoms. According to a particular embodiment of the composition,the homopolymer has a weight average molecular weight Mw comprisedbetween 5,000 and 20,000, preferably comprised between 10,000 and19,000. Preferably, the homopolymer is an olefinic ester of acrylic acidwith an alcohol comprising from 18 to 50 carbon atoms. Preferably, thehomopolymer is a polyacrylate comprising side hydrocarbon chains with 18to 40 carbon atoms.

Preferably, in the composition according to the invention, thefilterability additive is selected from copolymers and terpolymers ofethylene containing more than 20% of ester units, these ester unitsbeing themselves selected from esters of the vinyl acetate, vinylpropionate, alkyl acrylate and alkyl methacrylate type, taken alone oras a mixture, the alkyl group containing from 1 to 7 carbon atoms.According to a preferred embodiment, the filterability additives areselected from copolymers or terpolymers of ethylene and vinyl acetate,and/or of vinyl propionate, and/or of vinyl versatate, of ethyleneand/or (alkyl) acrylates, and/or (alkyl) methacrylates taken alone or asa mixture, comprising from 20 to 40% by weight of ester units. Accordingto a preferred embodiment, the filterability additives are selected fromthe copolymers or terpolymers of ethylene and vinyl acetate, and/orvinyl propionate and/or vinyl versatate, of ethylene and/or (alkyl)acrylates, and/or (alkyl) methacrylates, with a weight molecular weightcomprised between 3,000 and 20,000. According to a preferred embodiment,the composition according to the invention comprises from 85 to 98% byweight of copolymers of ethylene and of vinyl acetate comprising from 20to 30% by weight of vinyl acetate units and from 2 to 15% by weight ofpolyacrylate comprising side hydrocarbon chains with 18 to 40 carbonatoms and an average molecular weight ranging from 10,000 to 19,000.

According to another object, the invention relates to a hydrocarbondistillate comprising from 0 to 5,000 ppm of sulfur, and containing from10 to 5,000 ppm of said composition according to the invention,optionally mixed with other additives, detergents, dispersants,de-emulsifiers, antifoam agents, biocide agents, reodorant agents,cetane enhancers, anticorrosion agents, friction modifiers, enhancers oflubricity, combustion, cloud point, flow point, anti-sedimentation andconductivity. Preferably, the distillate comprises at least onehydrocarbon cut derived from the group formed by distillates with aboiling temperature comprised between 150 and 450° C., with an onsetcrystallization temperature Tcc greater than or equal to −5° C.,preferably comprised between −5° C. and +10° C., comprising thedistillates from direct distillation, in vacuo distillates, hydrotreateddistillates, distillates from catalytic cracking and/or hydrocracking ofdistillates in vacuo, distillates resulting from ARDS type conversionand/or viscosity breaking methods, distillates derived from valuation ofFischer Tropsch cuts, distillates resulting from BTL conversion ofvegetable and/or animal biomass, either taken alone or as a combination,and esters of vegetable and animal oils or their mixtures.

Preferably, the distillate comprises a content of n-paraffins containingmore than 18 carbon atoms larger than 4% by weight. Preferably, thedistillate comprises a content larger than or equal to 0.7% by weight ofn-paraffins, the carbon number of which is greater than 24. Preferably,the distillate comprises from 0.7-2% of n-paraffins with a carbon numberranging from C₂₄ to C₄₀.

According to another object, the invention relates to a diesel fuelcomprising 0 to 500 ppm of sulfur comprising at least one distillateaccording to the invention. According to another object, the inventionrelates to a heating fuel oil comprising from 0 to 5,000 ppm of sulfurcomprising at least one distillate according to the invention. Accordingto another object, the invention relates to a heavy fuel oil comprisingat least one distillate according to the invention. The inventionapplies to distillates which may be used as diesel fuel or heating fueloil further called domestic fuel oils. These distillates have an onsetcrystallization temperature or Tcc larger than or equal to −5° C.,preferably comprised between −5° C. and +10° C. This temperature Tcc ismeasured by DSC, this technique allowing determination of thetemperature at which the first paraffin crystals form, the lattergenerally corresponding to normal paraffins, with a chain length greaterthan or equal to 18 carbon atoms, paraffins with more than 24 carbonatoms being the first to crystallize when the temperature decreases.

The advantage of the present invention lies in the synergic effect ofthe use of so-called “revealing” compounds according to the invention,revealing the efficiency of conventional filterability or LFT additivesas regards reduction in the filterability temperature of thesehydrocarbon distillates resistant to the action of conventionalfilterability additives used alone. In this way, the invention isparticularly directed to the use of a revealing compound of thehomopolymer type in a hydrocarbon distillate comprising a weight contentof n-paraffins containing more than 18 carbon atoms larger than 4%. Moreparticularly, the hydrocarbon distillate comprises a weight content ofn-paraffins larger than or equal to 0.7%, the carbon number of which isgreater than 24. Preferably, the distillate is a cut with a boilingtemperature comprised between 150 and 450° C., and comprises a mixturefrom 0.7 to 2% by weight of n-paraffins having a carbon number rangingfrom C₂₄ to C₄₀.

The filterability additives of the invention are copolymers orterpolymers of ethylene containing more than 20% of ester units. Theseunits are of the vinyl acetate, vinyl propionate, vinyl versatate,(alkyl)acrylate, and (alkyl)methacrylate type, the alkyl groupcontaining from 1 to 7 carbon atoms. The preferred filterabilityadditives are selected from copolymers of ethylene and vinyl acetate,and/or of vinyl propionate and/or vinyl versatate, and/or of (alkyl)acrylates, and/or (alkyl) methacrylates, either taken alone or as amixture, comprising from 20 to 40% by weight of ester units. Preferably,the filterability additives used in the invention are copolymers orterpolymers with a weight molecular weight comprised between 5,000 and20,000. These copolymers or terpolymers have ester contents comprisedbetween 20% and 40%.

The additives revealing the efficiency of filterability additivesaccording to the invention are homopolymers obtained by polymerizationof an olefinic ester of acrylic acid optionally substituted with analkyl group having 1 to 7 carbon atoms, and of an alcohol comprisingmore than 16 carbon atoms, preferably from 18 to 50 carbon atoms. Thehomopolymer has a weight average molecular weight Mw comprised between5,000 and 20,000 and preferably comprised between 10,000 and 19,000.Preferably, the homopolymer is a polyacrylate comprising sidehydrocarbon chains with from 18 to 40 carbon atoms.

The efficiency of the revealing compound varies according to its weightmolecular mass, to the chain length of the alcohol and to the nature ofthe carboxylic acid used for synthesizing the ester. The homopolymersaccording to the invention for revealing the efficiency of conventionalfilterability LFT additives are selected from a set of polyacrylatesuseful for improving the flow point of the easy-to-treat distillates.However, they are not efficient for revealing a synergy effect withconventional LFT additives.

The distillates at which the invention is aimed are selected fromdistillates with a boiling temperature comprised between 150 and 450° C.and with an onset crystallization temperature larger than or equal to−5° C., preferably comprised between −5° C. and +10° C., comprising thedistillates from direct distillation, in vacuo distillates, hydrotreateddistillates, distillates stemming from catalytic cracking and/orhydrocracking of distillates in vacuo, distillates resulting from ARDStype conversion and/or viscosity breaking methods, distillates fromvaluation of Fischer Tropsch cuts, and distillates resulting from BTLconversion of vegetable and/or animal biomass, and distillatescontaining alkyl esters of vegetable or animal oils and/or theirmixture.

Another object of the invention is a synergic composition of additivesdedicated to distillates with a boiling temperature comprised between150° C. and 450° C., at an onset crystallization temperature close tozero, notably comprised between −5 and +10° C. This synergic compositioncomprises a mixture consisting of a filterability additive and of ahomopolymer according to the invention in a ratio producing a synergiceffect as regards the filterability temperature LFT of the distillatesaccording to the invention, LFT being measured according to the NF EN116standard. More particularly this composition comprises 85 to 99% byweight of at least one filterability additive based on a copolymer orterpolymer of ethylene and of a vinyl ester of a carboxylic acid with 3to 5 carbon atoms and of a monoalcohol comprising from 1 to 10 carbonatoms, and from 1 to 15% by weight of a homopolymer of an olefinic esterof a carboxylic acid with 3 to 12 carbon atoms and of a fatty alcoholcomprising more than 16 carbon atoms.

In this composition, the homopolymer has a weight average molecularweight Mw comprised between 5,000 and 20,000, preferably comprisedbetween 10,000 and 19,000. It is an olefinic ester of acrylic acid withan alcohol comprising from 18 to 50 carbon atoms. Preferably, thehomopolymer is a polyacrylate comprising side hydrocarbon chains withfrom 18 to 40 carbon atoms.

The filterability additives suitable for said composition according tothe invention are selected from copolymers and terpolymers of ethylenecontaining more than 20% of ester units, these ester units beingthemselves selected from esters of the vinyl acetate, vinyl propionate,(alkyl)acrylate and (alkyl)methacrylate type, the alkyl group containingfrom 1 to 7 carbon atoms. Preferably, these filterability additives areselected from copolymers or terpolymers of ethylene and vinyl acetate,and/or vinyl propionate, and/or vinyl versatate, of ethylene and/or(alkyl) acrylates, and/or (alkyl) methacrylates, comprising from 20 to40% by weight of ester units. These polymers or terpolymers have aweight molecular mass comprised between 3,000 and 20,000. In a preferredembodiment of the invention, the composition will comprise from 85% to98% by weight of ethylene and vinyl acetate copolymers comprising from25 to 30% by weight of vinyl acetate units and from 2 to 15% by weightof polyacrylate comprising side hydrocarbon chains with from 18 to 40carbon atoms and with an average molecular weight ranging from 10,000 to19,000.

Another object of the invention relates to the hydrocarbon distillate,for which the sulfur content is comprised between 0 to 5,000 ppm andwhich comprises from 10 to 5,000 ppm of said composition, optionallymixed with other additives, detergents, dispersants, de-emulsifiers,biocidal agents, antifoam agents, reodorant agents, cetane enhancers,anticorrosion agents, friction modifiers, enhancers of lubricity,combustion, cloud point, flow point, antisedimentation and conductivity.This distillate according to the invention comprises a major portion ofat least one hydrocarbon cut having an onset crystallization temperatureTcc greater than or equal to −5° C., preferably comprised between −5° C.and +10° C., stemming from the group formed by distillates with aboiling temperature comprised between 150° C. and 450° C. comprising thedistillates from direct distillation, in vacuo distillates, hydrotreateddistillates, distillates stemming from catalytic cracking and/orhydrocracking of distillates in vacuo, the distillates resulting fromARDS type conversion and/or viscosity breaking methods, distillatesstemming from valuation of Fischer Tropsch cuts, distillates resultingfrom BTL conversion of vegetable and/or animal biomass, taken alone oras a combination, and esters of vegetable and animal oils or theirmixtures. These distillates comprise a content of n-paraffins containingmore than 18 carbon atoms, larger than 4% by weight, and preferablylarger or equal to 0.7% by weight of n-paraffins, the carbon number ofwhich is greater than 24. The distillates particularly reactive to saidcomposition comprise in their chemical composition from 0.7 to 2% ofn-paraffins having a carbon number ranging from 24 to 40, the n-paraffindistribution may be continuous or discontinuous, i.e. all the familiesof n-paraffins are present or some are absent, thereby formingdiscontinuities notably when mixtures of distillates are made.

The invention is also directed to a combustion fuel, a fuel comprisingfrom 0 to 500 ppm sulfur and/or a domestic fuel oil comprising from 0 to5,000 ppm of sulfur or further a heavy fuel oil used as a combustionfuel in marine engines and in industrial boilers, these productscontaining a major portion of hydrocarbon base formed by at least onedistillate according to the invention and a corresponding minor portionof 50 to 5,000 ppm of a synergic composition of additives using arevealing compound according to the invention. This composition ofadditives may be present in the fuel or combustion fuel with at leastone additive from the group formed by additives, detergents,dispersants, de-emulsifiers, biocidal agents, antifoam agents, reodorantagents, cetane enhancers, anticorrosion agents, friction modifiers,enhancers of lubricity, combustion, cloud point, flow point,antisedimentation and conductivity.

DETAILED DESCRIPTION

With the purpose of illustrating the advantages of the presentinvention, examples are given as non-limiting examples.

EXAMPLE 1

This example describes the nature of the components of the invention andcomparative compounds. The distillates according to the inventionresistant to filterability or LFT (CFPP) additives alone are called Fiand the distillates non-resistant to these additives are called Gi. Theyare described in the Table I hereafter.

TABLE I G1 G2 F1 F2 F3 % of normal paraffins* <C₁₃ 4.53 2.86 2.05 1.770.41 C₁₃-C₁₇ 8.61 7.44 4.58 4.2 4.26 C₁₈-C₂₃ 5.47 4.02 4.64 4.31 9.38>C₂₄ 0.66 0.24 0.94 0.8 1.5 Total of n-paraffins 19.27 14.56 12.21 11.0815.56 LFT(° C.) −4 −8 1 0 7 FT (° C.) −12 −15 −6 — 6 CPT(° C.) −4 −7 2 07 Density 0.8327 0.8414 0.8541 0.863 0.870 Sulfur in ppm 39.8 320 9301240 1950 Viscosity at 40° C. mm²/s 2.725 2.752 2.6348 — — Cetane ascalculated 50.1 50.2 44.8 — — according to ASTM D4737 IP391 aromaticcontent Monoaromatics % 22.7 23 26.6 27.6 — Diaromatics in % 6.2 5.5 9.18.2 — Polyaromatics in % 0.6 1.2 1.9 3.3 — TCC (° C.) −7/−6.2 −8.3 −1.2−1.2 5 D86 distillation (° C.) Initial point 167.6 176.8 156.4 162.6164.1 T10 203 207.6 189.8 195.5 T20 224.7 225.6 203.5 220.7 T50 274.5270.7 271.9 293.6 T80 317.1 314.1 331.3 341 T90 337.4 333.2 354.3 357360 T95 353.9 345.9 371.1 372 Final point 356 352.2 373.4 382.8 *% byweight of paraffins determined by liquid chromatography/gaschromatography coupling FT = Flow temperature LFT = Filterabilitytemperature CPT = Cloud point temperature as measured by ASTM D2500 orEN 23015 TCC = Onset crystallization temperature as measured byDifferential Scanning Calorimetry Analysis (ACD or DSC) or according toIP 389-93.

The FT temperature or flow point measured for distillates used as fuelsis the lowest temperature at which the hydrocarbon is still able toflow. The CPT or cloud point temperature is a visual appreciation of thegermination and crystallization of paraffins, this measurement is lessaccurate than that of the onset crystallization temperature Tcc. TheLFT, the limiting filterability temperature of crystals of paraffinsprecipitating in hydrocarbons at low temperature, is intermediatebetween both of these extreme temperatures FT and Tcc: it is intendedfor appreciating the temperature at which the size of the crystals isstill sufficiently small for not blocking the filters.

Generally, the respective variations of LFT, FT and Tcc are notnecessarily related to each other and are more often dependent on thechemical composition of the products. Examples of distillates F1, F2, F3according to the invention have an n-paraffin content greater than orequal to 0.7% and a Tcc>−5° C., while distillates G1, G2 have ann-paraffin content less than 0.7% and Tcc<−5° C. The distribution of theparaffins is determined by liquid/gas chromatography. With this methodit is possible to determine the C9-C30 n-paraffin concentration inmiddle distillates.

In a first step, with liquid chromatography, it is possible to separatethe middle distillate according to chemical families (saturated, mono-,di- and tri-aromatic families). As the n-paraffins are in the saturatedfraction, the latter is recovered and injected on a gas chromatographycolumn where the paraffins are separated according to their boilingtemperature and therefore to their carbon number. Finally, the paraffinsare quantified by calibration.

The filterability additives used are copolymers of ethylene and vinylacetate referenced hereafter as EVAi in Table II hereafter.

TABLE II Viscosity at Vinyl acetate Molecular 100° C. content weight (Pa· s) (weight %) Mw EVA 1 0.3 28 9,500 EVA 2 0.4 31 15,000 EVA 3 0.4 3618,000 EVA 4 0.3 24 10,000

The revealing compounds used are polyacrylates referenced as Bi, thecharacteristics of which are given for 30% of active materials in anaromatic solvent of the Solvarex 10 type (aromatic hydrocarbon cut with8 to 20 carbons and a boiling point varying from 140 to 320° C.) inTable III hereafter. As preparation examples, these polyacrylates areobtained by polymerization of the monomer under an inner nitrogenatmosphere as follows.

100 parts of this monomer are melted beforehand in an oven at 70° C. andthen solubilized in 158 parts of aromatic solvent (Solvarex 10 orSolvarex 150). The obtained mixture is continuously introduced for 6 hrs30 and under stirring in a tank under a nitrogen atmosphere containing75 parts by weight of aromatic solvent and 4 parts by weight of organicperoxide, this mixture having been raised beforehand to a temperature of100° C. Throughout the addition, the set temperature is maintained at100° C. The reactor is cooled and the resin is stabilized by adding 100ppm of 4-methoxyphenol, in order to avoid post-polymerization of theresidual monomers which may lead to a change in the average molar massof the polymers during storage.

TABLE III Acid Mw, content Density Viscosity Viscosity Mn by (mg at 20°C. at 20° C. at 40° C. CPG Monomer KOH/g) (kg/L) (mm/s) (mm/s) (daltons)B1 C₁₈/C₂₂ 1.5 0.895 15 5,000 15,000 acrylate B2 C₃₀/C₄₀ 0.5 Not SolidSolid 6,770 acrylate mea- surable

EXAMPLE 2

The present invention aims at showing the benefit of Bi revealingcompounds according to the invention and their influence on theefficiency of LFT additives on distillates Fi of the invention and on Gidistillates. Table IV gathers the results obtained by comparing theefficiency of B1, either alone or in combination with the LFT additivesEVA 1 and EVA 2 on the Fi and Gi distillates.

TABLE IV Amount in ppm G1 G2 F1 F2 F3 Distillate alone −4 −8 1 0 7 Tcc−7 −8.3 −1.2 −1.2 5 EVA 1 100 −7 −10 −7 1 7 200 −13 −10 −11 3 7 300 −13/ / 4 7 EVA 2 100 −8 −9 4 3 / 200 −11 −17 3 2 / EVA1/B1 100 −8 −9 −11 // 95.5/4.5 200 −11 −10 −10 −6 −7  300 −14 / / −8 −10  EVA2/B1 100 / −10/ / / 95.5/4.5 200 / −19 / −6 −10  B1 4.5 −4 −8 1 0 7 9.5 −4 −8 1 1 8

It is observed that the Fi distillates with Tcc greater than −5° C. arenot or not very reactive to EVAi alone but are reactive to synergicmixtures EVAi/Bi while the Gi distillates outside the invention with Tccless than −5° C. are only reactive to the EVA alone. It is to be notedthat the revealing compound B alone does also not show any LFTefficiency on either of the families of Fi or Gi distillates.

EXAMPLE 3

The present example describes the influence of the relativeconcentration of the revealing compounds Bi and of the LFT additivesEVAi on the reduction of LFT temperatures of Fi distillates typical ofthe invention. Table V gathers the filterability temperatures of thedistillates F1 and F2 when the concentration of the revealing compoundBi is varied for variable concentrations of the EVAi/Bi composition.

TABLE V 0 100 200 F ppm ppm ppm F1 EVA1 1 −7 −11 F1 EVA1/B1: 97.8/2.2 1−13 −11 F1 EVA1/B1: 95.5/4.5 1 −11 −10 F1 EVA1/B1: 90/10 1 −11 −11 G1EVA1 −4 −15 −17 G1 EVA1/B1: 96/4 −4 −15 −17 G1 EVA1/B1: 92/8 −4 −12 −14G1 EVA1/B1: 82/18 −4 −8 −11

The conducted tests by varying the EVA1/B1 ratio show in the case of Fidistillates, an optimum efficiency for small doses of revealingcompound. When taking Gi distillates, a loss of efficiency of the EVA1sis seen on the contrary with increasing concentration of revealingcompounds Bi, expressed by an increase in the filterability temperatureof the distillate.

EXAMPLE 4

The present example describes the preferred polymers of the inventionselected from the polymers of olefinic esters of carboxylic acids and ofan alcohol. The question is of describing the impact of the nature ofthe carboxylic acid and that of the chain length of the alcohol on thedecrease of the filterability temperature of the F1 and F2 distillates.In the composition according to the invention, the content ofhomopolymers of olefinic esters of carboxylic acids and of an alcohol is4.5% for an EVA1 content of 95.5%. The composition content in thedistillates varies from 0 to 300 ppm in the present example.

The obtained results are gathered in Table VI hereafter,

TABLE VI Monomer used for Mw synthesizing the revealing (revealing 0 200300 compound B compound) ppm ppm ppm F2 Without — 1 4 3 F2 B1 C₁₈/₂₂acrylate 13,370 1 −6 −6 F2 C₁₈₋₂₂ methacrylate 17,100 1 3 F2 C₁₆ stearylmethacrylate 16,100 1 4 F2 C₁₂ lauryl methacrylate 11,985 1 3 2 F2C₃₀/₄₀ acrylate 6,764 1 0 −7 F2 C₁₆ stearyl acrylate 13,660 1 5 3 F2 C₁₂lauryl acrylate 14,030 1 3 4 F1 Without — 1 −7 −11 F1 B1 C₁₈₋₂₂acrylate/2-ethyl- 7,649 1 0 −1 hexyl acrylate: 80/20 F1 B1C₁₈₋₂₂/2-ethyl-hexyl 7,555 1 0 −2 acrylate: 50/50 F1 B1 C₁₈₋₂₂acrylate/vinyl 9,701 1 0 −2 acetate: 70/30 F1 B1 C₁₈₋₂₂/isobomyl 8,382 10 −1 acrylate: 70/30 F1 B1 C₁₈₋₂₂ acrylate 8,000 1 −11 −10

The efficiency of the revealing compound varies depending on the chainlength of the alcohol and on the nature of the carboxylic acid used forsynthesizing the polyester. In Table VI above, efficiency tests werecarried out with revealing compounds synthesized by homopolymerizationof alkyl acrylates with a chain length varying from C₁₂ to C₄₀(according to the operating procedure described in Example 1). Theseresults clearly show that the positive effect of the revealing compoundoccurs for polymers consisting in majority of alkyl chains above C₁₆.Best results are obtained with C₁₈-C₂₂ acrylate and C₃₀-C₄₀ acrylate.

Other tests by replacing the revealing compound B1 with polymerssynthesized by copolymerization of the C₁₈-C₂₂ acrylate with vinylacrylate (ratio: 70/30) or with 2-ethyl-hexyl acrylate (ratio 80/20 and50/50) show that these copolymers are not efficient as compared with thecorresponding C₁₈-C₂₂ homopolymers. They even have a detrimental effectas regards the LFT temperature of the distillates according to theinvention. The nature of the carboxylic acid is also a significantparameter, the tests described above carried out by replacing B1 withhomopolymers of esters of C₁₂, C₁₆ or C₁₈-C₂₄ methacrylic acids showthat they are not as efficient as their homologs obtained byhomopolymerization of esters of acrylic acid. This example actuallyshows that the required selection of the polyacrylates of the inventionas a revealing compound of the efficiency of the filterability additiveson the filterability temperature of the distillates of the type of theinvention is not obvious in view of the prior art. Only with thesynergic combination of the composition according to the invention, theproblem of lowering the LET temperature of distillates with Tcc greaterthan or equal to −5° C. may be solved.

1. A composition comprising a mixture further comprising: A) afilterability additive based on a copolymer and/or terpolymer ofethylene and of a vinyl ester of a carboxylic acid with 2 to 5 carbonatoms and of a monoalcohol comprising 1 to 10 carbon atoms; and B) apolvacrylate comprising side hydrocarborn chains with 18-40, wherein thepolyacrvlate is not a polymethacrylate; A and B being in a ratioproducing a synergic effect as regards the filterability temperature LFTas measured according to the NF EN116 standard, of hydrocarbondistillates with a boiling temperature comprised between 150 and 450° C.and an onset crystallization temperature as measured by differentialscanning calorimetry analysis greater than or equal to −5° C.
 2. Acomposition comprising (A) from 85 to 99% by weight of at least onefilterability additive based on a copolymer and/or terpolymer ofethylene and of a vinyl ester of a carboxylic acid with 2 to 5 carbonatoms, of a monoalcohol comprising 1 to 10 carbon atoms; and (B) from 1to 15% by weight of a polyacrylate comprising side hydrocarbon chainswith 18-40 carbon atoms, wherein the polyacrylate is not apolymethacrylate.
 3. The composition according to claim 2, wherein thepolyacrylate has a weight average molecular weight Mw comprised between5,000 and 20,000. 4-5. (canceled)
 6. The composition according to claim2, wherein the filterability additive is selected from copolymers andterpolymers of ethylene containing more than 20% of ester units, theseester units being themselves selected from esters of the vinyl acetate,vinyl propionate, alkyl acrylate, and alkyl methacrylate type, takenalone or as a mixture, the alkyl group containing 1 to 7 carbon atoms.7. The composition according to claim 2, wherein the filterabilityadditives are selected from copolymers or terpolymers of ethylene andvinyl acetate, and/or vinyl propionate, and/or vinyl versatate, ofethylene and/or (alkyl)acrylates, and/or (alkyl)methacrylates, takenalone or as a mixture, comprising 20 to 40% by weight of ester units. 8.The composition according to claim 2, wherein the filterabilityadditives are selected from copolymers or terpolymers of ethylene andvinyl acetate, and/or vinyl priopionate, and/or vinyl versatate, ofethylene and/or (alkyl)acrylates, and/or (alkyl)methacrylates, with aweight molecular weight comprised between 3,000 and 20,000.
 9. Thecomposition according to claim 2, further comprising from 85 to 98% byweight of copolymers of ethylene and vinyl acetate comprising 25 to 30%by weight of vinyl acetate units and 2 to 15% by weight of polyacrylatecomprising side hydrocarbon chains with 18 to 40 carbon atoms and withan average molecular weight ranging from 10,000 to 19,000.
 10. Ahydrocarbon distillate comprising from 0 to 5,000 ppm of sulfur,containing from 10 to 5,000 ppm of the composition according to claim 1,optionally mixed with other additives, detergents, dispersants,de-emulsifiers, antifoam agents, biocidal agents, reodorant agents,cetane enhancers, anticorrosion agents, friction modifiers, enhancers oflubricity, combustion, cloud point, flow point, antisedimentation andconductivity.
 11. The distillate according to claim 10 furthercomprising at least one hydrocarbon cut derived from the group formed bythe distillates with a boiling temperature comprised between 150 and450° C., with an onset crystallization temperature Tcc greater than orequal to −5° C., comprising the distillates from direct distillation, invacuo distillates, hydrotreated distillates, distillates stemming fromcatalytic cracking and/or hydrocracking of distillates in vacuo,distillates resulting from ARDS type conversion and/or viscositybreaking methods, distillates stemming from valuation of Fisher Tropschcuts, distillates resulting form the BTL conversion of vegetable and/oranimal biomass, taken alone or as a combination, and esters of vegetableand animal oils or their mixtures.
 12. The distillate according to claim10, further comprising a content of n-paraffins containing more than 18carbon atoms, greater than 4% by weight.
 13. The distillate according toclaim 10, further comprising a content greater than or equal to 0.7% byweight of n-paraffins, the carbon number of which is greater than 24.14. The distillate according to claim 10, further comprising from 0.7 to2% of n-paraffins having a carbon number ranging from C₂₄ to C₄₀.
 15. Adiesel fuel comprising from 0 to 500 ppm of sulfur comprising at leastone distillate according to claim
 10. 16. A heating fuel oil comprisingfrom 0 to 5,000 ppm of sulfur comprising at least one distillateaccording to claim
 10. 17. A heavy fuel oil comprising at least onedistillate according to claim
 10. 18. The composition according to claim1, wherein the filterability additive is based on a copolymer and/orterpolymer of ethylene and of vinyl acetate or of ethylene and a vinylester of a carboxylic acid with 3 to 5 carbon atoms and of a monoalcoholcomprising 1 to 10 carbon atoms.
 19. The composition according to claim2, wherein the filterability additive is based on a copolymer and/orterpolymer of ethylene and of vinyl acetate or of ethylene and a vinylester of a carboxylic acid with 3 to 5 carbon atoms and of a monoalcoholcomprising 1 to 10 carbon atoms.